<!DOCTYPE html>
<html>
<meta charset="UTF-8">
<body>

<script>
   function Person() {

   }
   Person.prototype={
//       mount:function(){
//             console.log('mount')
////            return   mount();
//
//
//       }
   }
   var mount  =  Person.prototype.mount||()=>{};
   Person.prototype.mount=function () {
       mount.call(this);
   }
  var  _person=new Person()
   _person.mount();

</script>



</body>
</html>
